Flexible sensors have demonstrated great potential for utilization in many industrial applications due to their ability to be produced in complex shapes. Sensors are employed to monitor and detect changes in the surrounding environment or the structure itself. A great majority of these flexible structures are produced by casting processes, since they are generally composed of silicone materials due to their high elasticity and flexibility. Unfortunately, the casting process is time consuming, and it limits the development of complex geometries reducing the advantages of silicone materials. 3D printed flexible sensors have demonstrated great potential for utilization in a variety of different applications including healthcare, environmental sensing, and industrial applications. In recent years, research on these topics has increased to meet low-cost sensing needs due to the development of innovative materials and printing techniques that reduce cost, production time, and enhance the electrical and mechanical properties of the sensors. This paper presents a 3D printed flexible dielectric electroactive polymer (DEAP) sensor capable of producing an output signal based on the deformation caused by external forces. Three different conductive flexible filaments were tested, using one commercial filament and two custom-made filaments, a comparison of its sensing behavior is also presented herein. Additionally, computational simulations were done to evaluate the performance of the produced sensors, evaluating the capacitance change of the entire structure. This work demonstrates the production of 3D printed flexible sensors and studies the behavior of new customizable conductive flexible filaments. Both manufactured sensors were produced using fused deposition modeling (FDM) techniques.